The bottoms of conventional shoes, regardless of the design or the purpose of the shoes, have a forward sole supporting portion and a rearward heel supporting portion. As the wearer walks or runs, the heel typically strikes the ground first and the force or pressure of the contact is transmitted initially through the heel to the ground.
In those types of shoes which have heel portions formed of a resilient or rubber-like material, the heel contacting force against the ground is absorbed, to some extent by the heel portion. The resiliency of the heel portion makes the step somewhat more comfortable for the wearer as compared with a hard, for example, leather type, heel. However, even with relatively soft, resilient heel portions, after a considerable period of walking or running, the initial impacts between the heel and the ground adversely affect the wearer's foot heel portion. Thus, it would be desirable to provide a shoe heel portion which more readily spreads out the initial contacting impact against the ground so as to reduce the reaction forces to the wearer's foot and, thereby, make the shoe more comfortable for a long period of time. In addition, it would be desirable, if feasible at low cost, to return a portion of the normal energy expended during walking or running to the wearer's foot for reutilization in the walking and running movement. Further, there is a need to reduce the fatigue in leg muscles which are caused by long periods of walking or running and which are typically experienced by most people.
Consequently, the invention herein relates to a springy support for the heel portion of a shoe which functions to make the shoe more comfortable, particularly after long periods of walking or running, as well as to return a substantial portion of the energy of ground impact to the wearer's foot in a useful form.